Pearl... or egg?
These fingernail-sized eggs sit atop beds of kelp and strongly resemble teal pearls. It's easy to mistake the two and accidentally harvest a handful of eggs rather than a shelled mollusk's pretty prize. This is not an ideal situation.
Vandaos are full of perplexing trickery and nonsense. These creatures never grow larger than a reasonably sized rabbit, and they thrive off chaos in a way that makes them unsuitable pets or companions. It's best to leave them in the ocean where they live rather than attempting to tame them.
These water elementals lay their eggs atop kelp beds as if for protection from other water-dwelling creatures. It's not fully understood why this is as the eggs glitter in the sunlight and are not well hidden. For whatever reason, they are still fairly high on the food chain and few other creatures dare to eat these eggs.
The Vandao are fast underwater and have been known to take nasty bites out of unwary swimmers' legs if they stray too close. These bites are quick to become infected without proper medical treatment. When removed from their watery homes and placed on land they don't dry out like most water creatures. They simply hunker down and open their mouths wide, letting an endless and puzzling supply of putrid-smelling water pour out until they're put back. They are truly a nuisance and should not be handled.